Reaction Pathway and Rate-Determining Step of the Schmidt Rearrangement/Fragmentation: A Kinetic Study
作者:Ryo Akimoto、Takehiro Tokugawa、Yutaro Yamamoto、Hiroshi Yamataka
DOI:10.1021/jo300419c
日期:2012.4.20
pre-equilibrium in the formation of iminodiazonium (ID) ion and that the N2 liberation from the ID ion is rate-determining. Under high azide concentration conditions, where the effective reactant is the ID ion, the reaction gave a linear Hammett plot with a ρ value of −0.50. The observed substituent effects on the rate and the product selectivity imply that path bifurcation on the way from the rate-determining
三甲基叠氮化硅在90%(v / v)的TFA水溶液中将3-苯基-2-丁酮与取代的3-苯基-2-丁酮进行Schmidt重排,生成了两种类型的产物:碎片和重排,其比例取决于取代基:碎片越多,电子越多-供体取代基。通过固氮法进行的速率测量表明存在诱导期,并且拟一级反应速率常数显示出相对于叠氮化物浓度的饱和动力学。结果表明,反应通过预平衡进行,形成亚氨基重氮(ID)离子,并且N 2从ID离子的释放是决定速率的。在高叠氮化物浓度的条件下,其中有效反应物是ID离子,该反应给出了ρ值为-0.50的线性Hammett图。如先前的分子动力学模拟所示,观察到的取代基对速率和产物选择性的影响暗示着从速率确定TS到产物态的路径发生分支,类似于贝克曼重排/片段化反应。